A vertical cavity surface emitting laser device (VCSEL) is capable of emitting a laser beam perpendicular to its top surface. There are wide applications in connection with VCSEL, such as data communication, absorption spectroscopy, optical sensor, etc.
Referring to FIG. 1, a conventional vertical cavity surface emitting laser device 900 includes a substrate 901, a bottom distributed Bragg reflector 902 disposed on the substrate 901, an active layer 903 disposed on the bottom distributed Bragg reflector 902, a top distributed Bragg reflector 904 disposed on the active layer 903, a top electrode 905 disposed on the top distributed Bragg reflector 904, a bottom electrode 906 connected to the substrate 901 opposite to the bottom distributed Bragg reflector 902, and a confinement member 907 formed in the top distributed Bragg reflector 904 and defining an aperture 908 through which a laser beam emitted by the active layer 903 passes.
When operating the conventional VCSEL 900, the top electrode 905 and the bottom electrode 906 are connected to an external power source (not shown) to provide electrical energy to the active layer 903, which then emits a laser beam 910 that oscillates between the top distributed Bragg reflector 904 and the bottom distributed Bragg reflector 902, and eventually exits the conventional vertical cavity surface emitting laser device 900 through the aperture 908 defined by the confinement member 907. Various techniques may be used for forming the confinement member 907. For instance, the top distributed Bragg reflector 904 may be partially implanted with protons or partially oxidized by high temperature to form the confinement member 907. In order not to damage the active layer 903 when forming the confinement member 907, a gap is left between the active layer 903 and the confinement member 907. However, electric current tend to leak through a portion 911 of the gap.
Therefore, it is desired to suppress such current leakage.